The mission of the Mouse Phenotyping and Pathological Assessment (MPPA) Core is to provide the necessary expertise and infrastructure to assess the impact of removing senescent cells (Subproject 1) or their effects (Subprojects 2-4) on measures of physical function, body composition, immune status, and age related pathology. These outcomes of healthspan have been selected for their stand-alone importance and established relationships with frailty, disability, institutionalization, and longevity in older individuals. The ability to conduct these outcomes in mice will greatly enhance our ability to translate the basic biology of aging into clinical application; the overarching goal of the Program Project. The MPPA Core will also be responsible for the banking and distribution of tissues to organ system-based Theme Leaders, and advancing the Aging Animal Medical Record in partnership with the Administrative Core (Core A) and Systems Biology and Bioinformatics Core (Core C).